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Develop Mental Plant: About 1955, however, two other major types of plant hormones, the gibberellins and the cytokinins, were recognized. (The gibberellins had been known as long as auxin, but their significance had not been understood.) By 1965 two more substances had been added to the list of hormones: abscisin, or abscisic acid, and ethylene. The significance of these two advances—the cracking of the genetic code and the discovery of several new plant hormones—for develop mental plantmental plant biology is closely interrelated.
Nevertheless,, I consider these findings most exciting and significant for two reasons. For one, they were genuine "firsts"; the proof that gibberellin causes, in some way, de novo synthesis of at least two enzymes (and very probably more) in a target tissue, and the proof that it causes isolated cell nuclei to make new RNA, had no clear-cut counterpart with any other hormone or in any other system. In the past, experimental plant biology usually lagged behind work with animals, and particularly behind work with microorganisms. Now, develop mental plantmental biology of plants had not only caught up with that of animals and microorganisms but, in some areas at least, had taken the lead.
An offset is a plantlet that has develop mental planted laterally on a stem either above or below ground. They can be detached from their parent plant and grown on to make firm new plants.A runner is a more or less horizontal stem that arises from a crown bud and creeps overground. The leaves are normally scale-like, and rooting may occur at the nodes. The lateral buds develop mental plant as new plants, and eventually the stem of the runner deteriorates, leaving a new isolated plant.
This is a method of propagation in which a stem is encouraged to produce roots so that a new plant is formed while still attached to and nourished by the parent plant. Some shrubs layer themselves naturally: simply lift them from the soil, cut them from the parent plant and replant. The simplest way of propagating by layering is to select vigorous young shoots and to peg them down around the parent plant. First dig the soil around the main plant and prepare the shoot by cutting a notch halfway through at a leaf joint about 12in from its tip. After first treating the cut surfaces with a rooting powder, peg the shoot down.
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